The art is generally aware of aerosol can sprayer assemblies adapted to facilitate the actuation of the aerosol can by the hand of the user. Various strategies have been employed to reduce the chance for unintentional spraying of the aerosol can's contents. For example, Crowell, U.S. Pat. No. 3,373,908, shows a substantially unitarily molded sprayer assembly adapted to clip on to the rim of the valve cup of an aerosol can. The button to be pushed by a user in order to spray contents from the can is located within a valley formed in the body of the actuator. The valley and button are so designed that access to the button is limited to objects, such as a user's finger, capable of reaching down into the valley to the button. By this means, access to the button is sufficiently restricted that a flat surface or a rigid object that spans the valley is unable to depress the button and actuate the aerosol can. Nevertheless, objects small enough or so oriented as to reach the button in its valley still can activate the can, making unintentional spraying a possibility.
Demarest et al., U.S. Pat. No. 5,027,982, discloses the use of an overcap that attaches to an actuator, the actuator in turn being attached to the upper chime of an aerosol can. The chime of an aerosol can is the crimped joint at which the dome of the can's lid attaches to the cylindrical sides of the can. The '982 actuator has a button formed at one end of a sprayer arm that has a nozzle at its other end and a channel that communicates between the can's valve stem and the nozzle. The sprayer arm is hinged to the actuator at its nozzle end, allowing a user to actuate the can's valve by depressing the button, moving the sprayer arm downwardly against the valve stem.
The overcap of the '982 device rotates coaxially on the actuator. The overcap has two access ports that a user may align respectively with the button and the nozzle, one port enabling the user's finger to reach the button and the other port allowing spray from the nozzle to escape the overcap when the aerosol can is activated. The overcap may then be turned 90.degree. by the user, whereupon the actuator's button and nozzle are covered by the overcap.
A disadvantage of the '982 device is the attachment of the actuator to the chime of the can. The can's chime is the joint where the can's lid attaches to the sides of the can. The lid of a conventional aerosol can includes a dome. The dome is that part of the can lid that spans the distance between the chime of the can and the crimped joint that defines the rim of the valve cup. The valve cup is the central depression of a typical aerosol can lid, within which the can's valve is located.
The dome typically is fairly flexible, bulging upwardly or retreating downwardly as the relative pressure differential between the contents of the can and the ambient atmosphere changes. The valve cup is carried on the dome and moves with it. This fact makes the distance between the valve of an aerosol can and the structures of a chime-mounted actuator that must engage the valve stem difficult or even impossible to precisely regulate. In extreme instances, over filling or heating a can may cause its dome to bulge upwardly sufficiently far that the valve stem presses against the underside of the actuator and self-activates, causing unintended spraying. At the other extreme, a depressed dome may carry the valve stem sufficiently far away from the underside of the actuator that the can fails to spray, even when a user fully depresses the actuator's button.
Another difficulty with sprayer assemblies that mount on the chime of a can is that can chimes differ in diameter for each size of aerosol can. Different sized sprayer assemblies must be designed specifically to fit each can size. This requires two unique molds and parts inventories for each can size, if a two-part actuator/overcap assembly is being used. In contrast, most conventional aerosol cans, even if differing in overall can and chime diameter, nevertheless are made with standardized valve cups, one valve cup size serving for all. The difference in can diameters is accomplished by the use of larger or smaller can domes, not larger or smaller valve cups and valve structures.
Goncalves, U.S. Pat. No. 4,513,890, discloses a presentation cap that includes a first part that attaches to the valve cup rim and a second part that attaches, in turn, to the first part. The presentation cap serves to correctly orient the can in the user's hand, with the cap's most natural position in the hand causing the nozzle to be directed away from the user. The Goncalves presentation cap does not function to reversibly enclose and reveal its spraying mechanism.
Sette, U.S. Pat. No. 3,844,448, discloses a cam track element that attaches to the valve cup rim and an overcap that attaches to and turns on the cam track element. However, Sette's overcap has cam followers that engage and slide in cam tracks formed in the cam track element, pulling the overcap downwardly on the can as the overcap is turned. When the overcap is locked in a downwardmost location, overcap structures press upon and activate the can's valve to evacuate the contents of the can. Like Goncalves, Sette also does not function to reversibly enclose and reveal the device's spraying mechanism to regulate its availability for use.
A problem repeatedly encountered by the art is that of locking an aerosol can so as to prevent premature or unintended spraying, for example by shoppers in a store. Removable locking inserts have been devised to provide a tamper lock, such as the insert shown in Crowell, U.S. Pat. No. 3,373,908, at 50. Such locking inserts commonly are unitarily molded with a sprayer assembly and must be broken free before the sprayer can be activated. The arrangement is designed to allow a person intending to use the can to remove the locking insert with deliberate but only modest effort. At the same time, accidental bumps in the shipping process will not activate the can, and shoppers attempting to sample the can's contents by way of a quick spray in a store are at least discouraged. Once such a tamper lock has been removed, it usually cannot be replaced. While a tamper lock's undisturbed presence provides immediate assurance that none of a can's contents have been sprayed, such arrangements do not provide ongoing accidental use protection, once the can has been first used.
A need remains for a sprayer assembly that is practical to manufacture and assemble, that will reliably interact with the valve of an aerosol can, avoiding the complications of bulging or depressed can domes, that has major parts usable with conventional aerosol cans of differing diameters, and that provide means to reversibly enclose and expose the spraying structures of the assembly to discourage accidental discharge.